Mobile crane



March 11. 1969 IOBILE CRANE med Jan. :5. 1967 11- r 26. rice I M udge"WEN-roe Hffys.

United States Patent 8 Claims ABSTRACT OF THE DISCLOSURE A mobile craneadapted to be mounted on a vehicle body, trailer, dolly or otherwisesuitably supported, comprising an upright support mast, a boom assemblymounted on the mast, load-attaching means depending from the boomassembly, and load-lifting apparatus mounted within a protective housingsecured to the post. The load-lifting apparatus includes a rotatabledrum connected by means of a cable to the load-attaching means, a motormounted above the drum for driving the same oriented with the axis ofits shaft and disposed horizontally, and a speed reduction unitinterposed between the motor and drum providing a driving connectionbetween the two.

This invention relates to load-handling apparatus, and moreparticularly, to such apparatus which takes the form of a power-operatedcrane that may be mounted on the body of a vehicle, trailer, dolly orotherwise.

A common form of crane of the type indicated comprises an upright mastfor mounting on a vehicle, a boom assembly mounted on the mast, acable-operated, vertically-shiftable load-attaching device dependingfrom the boom, and power-operated mechanism for taking up and paying outa cable which connects with the load-attaching device. The usualpower-operated mechanism employed includes a rotatable drum upon whichthe cable is Wound, and an electric motor mounted below the drum andoperable to drive the same.

A crane of the type described may be mounted on a vehicle, such as atruck, which operates and remains out of doors a good part of the time.Thus, the crane is often exposed to, and is expected to withstand, harshweather conditions. Known devices, however, after extended periods ofsuch exposure, have frequently experienced motor failure causing thedevice to become inoperative, and requiring time-coming and expensiverepairs. Such failure has often resulted from water, due to rain orsnow, getting into and damaging the motor.

There are a number of reasons why such damage has occurred with knowncranes..For example, many cranes have no protective covers at all fortheir motors, and in such cases, water easily enters the motors throughthe usual ventilation openings provided in the motor housings. However,even on cranes where suitable protective covers are provided, waterdamage is still a problem. This results from the fact that water flowsalong the cable connected with the take-up drum and collects on thedrum. Water on the drum then drips onto the motor which, as indicatedabove, is usually mounted directly below the drum. This latter-mentionedproblem is compounded where, as in many cases the motor is oriented withits shaft disposed upright and a set of ventilating openings facingdirectly upwardly.

A general object of the present invention, therefore, is to provide anovel crane which avoids the above-indicated difficulties encounteredwith known cranes.

More particularly, an object of the invention is to provide sue-ha cranewhich employs an electric motor, and which includes novel meanssupporting the motor and protecting the same against water damage. Thus,the in- 3,432,145 Patented Mar. 11, 1969 vention provides novel housingstructure which forms an effective shield for the motor, shielding thesame from moisture outside the structure. The housing structureaccommodates mounting of the motor with the drive shaft thereof disposedhorizontally whereby the likelihood of any moisture entering theventilation openings of the motor is negligible.

Another object is to provide a crane of the type described which furtherincludes a rotatable drum driven by the motor, and a cable extendingbetween the drum and a load-attaching means for the crane, wherein thehousing structure accommodates mounting therein of the drum with suchlocated below the motor whereby any water which flows along the cableand collects on the drum cannot drip onto the motor.

The crane contemplated herein comprises an upright mast upon which thehousing structure is mounted. A further object of the invention is toprovide, in such an organization, housing structure of the type so fardescribed which includes portions thereof that function as a brace forthe mast.

These and other objects and advantages attained by the invention willbecome more fully apparent as the description which follows is read inconjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation of a crane as contemplated herein mounted onthe rear portion of a pickup truck, with portions of housing structureforming part of the crane broken away to illustrate load-lifting meansalso forming part of the crane; and

FIG. 2 is a view taken along the line 2-2 in FIG. 1, also with portionsof the housing structure broken away.

While a crane constructed according to the invention is described hereinin connection with mounting on a vehicle, it should be understood thatsuch is for the purpose of illustration only, and that the crane mayreadily be supported on other suitable means.

Turning now to the drawings, and with reference first to FIG. 1, showngenerally at 10 is the rear portion of a vehicle such as a pick-up truckhaving the usual truck body 12 including a floor 12a, and rear wheels14, supporting the body for travel over the ground.

Mounted on floor 12a, and indicated generally at 16, is a crane, orload-handling apparatus, as contemplated herein. The crane comprises anupright mast 18 having a pair of hollow cylindrical mast sectionsincluding a lower mast section 18a, the upper end of which is nestedwithin an upper mast section 18b. Upper section 18b is adapted to rotateabout lower section 18a, and is supported on the lower mast sectionthrough a suitable thrust bearing 20 (shown in dashed outline) which isappropriately mounted within the interior of section 18b and which seatson the top of mast section 18a. Further accommodating relative rotationof the two mast sections is a roller bearing assembly (not illustrated)which provides rolling contact between the outside of section 18a andthe inside of section 1811, and which is mounted within a collar 22secured adjacent the base of section 18b.

A suitable friction brake 23 is mounted on mast section 18b and isoperable releasably to clamp the two mast sections together, thus toprevent relative rotation between the sections.

The lower end of mast section extends downwardly through suitable boresprovided in a pair of substantially flat, horizontally disposed mountingplates 24, 26 and through a similar bore provided in floor 12a. Mountingplates 24, 26 are fastened against upper and lower sides, respectively,of the floor by means of fasteners, such as fasteners 28, and mastsection 18a is welded to upper mounting plate 24. A gusset 29 isprovided which is welded both to the lower mast section and to plate 24.

Supporting the portion of mast section 18a which extends downwardlythrough plate 26 is a hollow cylindrical sleeve 30 which freely receivesthe mast section and which is welded to plate 26. Elongated supportstruts, such as struts 32, are provided having one set of ends welded tothe outside of the sleeve and the other set of ends welded to plate 26.These struts provide support for the sleeve.

The crane further comprises an extensible boom assembly including anelongated, hollow, cylindrical section 34, and an elongated,cylindrical, extensible arms 36. Section 34, adjacent one end thereof,is provided with a diametrical bore 34a, and arm 36 is provided withplural diametrical bores 36a spaced along the length of the arm. Section34 and arm 36 are releasably locked together by means of a key 38 whichextends through bore 34a and an aligned bore 36a of the arm. The otherend of section 34 is pivotally mounted on mast section 181) by means ofpivot mounting 40. Suitably mounted on the outer end of arm 36 is apulley assembly 42 including a pulley wheel 42a.

Also forming part of the crane is an adjustable chain device 44 foradjusting the inclination of the boom relative to the mast. This deviceincludes an elongated clevis 46 having one end pivotally connected at 48to pulley assembly 42, and its other end connected by a pin 50 to oneend of an elongated chain 52. The chain, adjacent its other end,releasably engages a notched locking plate 54 secured to one end of anelongated fastener 56. The other end of fastener 56 is pivotallyconnected at 58 to a pulley assembly 60, including a pulley wheel 60a,secured adjacent the upper end of mast section 18b.

Considering FIGS. 1 and 2 together, shown generally at 62 adjacent thelower portion of mast section 18a is housing structure as contemplatedherein, and mounted within this housing structure is load-lifting means64 for the crane.

The housing structure includes a pair of elongated upright end plates,such as plate 66, welded to the outside of mast section 18a adjacentdiametrically opposite sides thereof. Plates 66 are also welded to thetop of mounting plate 24. Welded to the outside edges of plates 66, andalso to the top of plate 24, are laterally spaced, upright side members68, 70 also forming part of the housing structure. A base bar 72 isprovided which extends between side members 68, 70 and which is weldedto the top of mounting plate 24.

The housing structure further includes a detachable, somewhat L-shapedcover 74, which, in operative position as shown, spans the side membersand forms a top and end wall for the housing structure. The cover isprovided with suitable side flanges, such as flange 74a, which, with thecover in place, overlap the side members of the housing. The cover isalso provided with louvers 78 which enable ventilation of the equipmentmounted within the housing. The cover is held releasably in place byvirtue of frictional engagement with collar 22 which engages a margin ofthe same adjacent the mast, and with base bar 72 which engages a flange74b formed adjacent the base of the cover. The cover is formed of asuitable resilient material, such as a sheet steel, and when in place asshown is somewhat deformed whereby it is resiliently pressed againstcollar 22 and bar 72.

Considering now the construction of load-lifting means 64, in generalterms it includes a reversible electric motor 80, which may be operableon either AC. or DC. current, a speed reduction unit 82, and a rotatabledrum 84. Motor 80 is mounted adjacent the top of the housing, with itsshaft disposed horizontally, on a plate 86 which extends between and iswelded to side members 68, 70. The motor is held in place on plate 86 bysuitable fasteners, such as those shown at 88. The motor casing isprovided, adjacent opposite ends, with ventilation openings, such asopenings 80a (FIG. 2).

Speed reduction unit 82 is mounted below the motor by means of fasteners90 on a plate 92 which, like plate 86, extends between and is welded toside members 68, 70. The motor and .drive unit are connected together bymeans of belts, or belt drive means, 94 trained over pulleys 96, 98suitably secured to the output shaft of the motor and to the input shaftof unit 82, respectively. Unit 82 and belts 94 are also referred toherein collectively as connecting means.

Drum 84 is journaled for rotation about a substantially horizontal axisin suitable bearings, such as hearing 99 in FlG. 2, (not shown inFIG. 1) mounted on side members 68, 7t). Suitably secured to one end ofthe drum is a sprocket wheel 100. The drum is connected to speedreduction unit 82 by means of a chain 102 which passes through asuitable opening 92a in plate 92 and which is trained over wheel 1%, anda sprocket wheel 164 secured to the output shaft of unit 82.

A pulley assembly 1%, including a pulley wheel 1060 is provided adjacentthe base of the housing structure. This assembly is secured to mastsection 18b adjacent an opening, or passage, 168 provided in the side ofthe mast section. Opening 108 communicates with the interiors of housing62 and mast section 18b.

Crane 16 further includes a block, or load-attaching means, 110including a pulley wheel 110a depending from the boom assembly as shown.The block is connected to drum 84 by means of an elongaed cable, ortensioning element, 112. The cable has one end connected at 114 topulley assembly 52, its other end wound on drum 84, and between its endsis trained over pulleys 110a, 42a, 60a and 166a.

Power is supplied to motor 80 from a suitable source (not shown) throughcable 116 which extends through a suitable opening provided in thehousing and which connects with the source. A suitable control (notillustrated) is connected to the cable for controlling the flow of suchpower whereby the motor may be operated in either direction and stopped.

Explaining the protection afforded motor 80 with the construction shown,with cover 74 in place as illustrated, the housing structure provides aprotective shield for the motor, shielding it from moisture outside thehousing. Further protection results from the fact that the motor isoriented with its drive shaft, and hence its ventilating opeings,disposed horizontally whereby during times that the cover is removed,moisture cannot fall into the motor casing through such openings.

With drum 84 mounted below the motor, and cable 112 ntering the housingthrough passage 108 which is located at a point also below the motor, nowater which may flow along the cable and collect on the drum can driponto the motor.

Cover 74, which is held in place only due to frictional engagement withcollar 22 and bar 72, may readily and quickly be removed for inspectionand maintenance of the various apparatus mounted within the housingstructure, and the cover is provided with louvers which enableventilating of such apparatus without permitting rain or snow water toenter the housing. With the motor thus protected, the crane can readilywithstand long periods of outside exposure without danger of the motorfailing due to water damage.

The end plates and side members forming part of the housing herein, alsoact as a brace supporting mast section 1817.

While an embodiment of the invention has been described herein inconnection with a particular type of crane, it is appreciated that theinvention may be used as well with other types of load-handlingapparatus. It is appreciated also that variations and modifications maybe made in the invention without departing from the spirit thereof.

It is claimed and desired to secure By Letters Patent: 1. Inload-handling appartus in operative position including an upright mast,a boom assembly mounted on said mast, and load-attaching meansoperatively connected to said boom assembly,

housing structure including a pair of spaced-apart lateral side membersmounted on said mast, and

load-lifting means located within said housing structure for raising andlowering said load-attaching means and any load attached theretocomprising a rotatable drum located between and journaled on said sidemembers, operatively connected to said load-attaching means, an electricmotor mounted on a support means located between said side members abovesaid drum, and

means connecting said motor and said drum producing a driving connectiontherebetween whereby operation of said motor causes rotation of saiddrum.

2. The apparatus of claim 1 which further includes an elongatedtensioning element operatively interconnecting said drum and saidload-attaching means, extending into said housing structure at a pointlocated below said motor.

3. The apparatus of claim 2, wherein said mast includes an elognatedhollow mast section having means adjacent the base thereof defining apassage communicating with the interior of the mast section and housingstructure atv said point below said motor, and said tensioning elementextends along and through said mast section, and into said housingstructure through said passage.

4. The apparatus of claim 2, wherein said motor is mounted with itsshaft extending substantially horizontally.

5. The apparatus of claim 4, wherein said means connecting said motorand said drum comprises a speed reduction unit mounted on said sidemembers between said motor and said drum, and belt drive meansoperativel interconnecting said motor and said unit.

6. The apparatus of claim 5, wherein said housing structure furtherincludes upright elongated end plates adjacent an end thereof joiningsaid side members to said mast, and, together with said mast closing offsaid end of said structure, said end plates and side members actingtogether as a brace for said mast.

7. The apparatus of claim 5, wherein said housing structure furtherincludes a detachable cover, in operative position detachably mounted onsaid side members.

8. The apparatus of claim 5, wherein said speed reduction unit ispositioned below said motor,

References Cited UNITED STATES PATENTS 1,440,722 1/ 1923 Dunnam 212-2,804,979 9/1957 Lassiter 212-59 2,923,418 2/1960 McGuire 212-592,940,621 6/1960 White 212-59 3,235,229 2/1966 Buschbom 254-1863,306,467 2/1967 Weempe 212-55 2,531,346 11/1950 Schuchert 187-22,565,091 8/1951 Reed 212- 2,974,809 3/1961 Sellars 212-34 3,048,3718/1962 Klimek 254-187 3,276,546 10/1966 Slais 187-2 EVON C. BLUNK,Primary Examiner. HARVEY C. HORNSBY, Assistant Examiner.

US. Cl. X.R. 212-59

